Automatic musical instrument



C. F. STODDARD.

AUTOMATIC MUSICAL INSTRUMENT. APPLICATION FILED NOV. 26. 1917. RENEWEDDEC. 19,1921.

' Patentefl Mar. 14,1922.

, understood in the art. A wind trunk 7 UNITED STATES PATENT OFFICE.

CHARLES E. STODDARD, OF NEW YORK, N. ii, ASSIGNOR, T0 AMERICAN PIANOCOMPANY; OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

AUTOMATIG MUSICAL INSTRUMENT.

Specification of Letters Patent.

Patented Mar. 14, 1922.

Application filed November 26, 1917, Serial No. 203,893. RenewedDecember 19, 1921. Serial No. 523,586.

To all whom it may concern:

Be it known that I, CHARLES F. Sron- DARD, a citizen of the UnitedStates of America, residing in the cityof New York, in the county andState of New York, have invented an Improvement in Automatic MusicalInstruments, of which the following is a s ecification.

his invention relates to automatic means for playing musicalinstruments, such as pianos, and pertains more particularly to means forgoverning and varying tone intensities.

Among other objects the invention provides means to vary the generalrange of expression changes, which may be preferably combined withautomatic expression governing and regulating mechanism. Such expressiongoverning and regulating mechanism may have, if desired, the three-foldcapacity for producing incremental changes in playing intensities; formaintaining uniform any given playing intenslty, whether one or manynotes are simultaneously sounded; and p for producing substantiallycontinuous 'progressive changes in playing intensities. For this purposethe invention may be embodied in an apparatus which is very simple andreliable in operation.

For illustration, the accompanying drawings show one practicableembodiment of the invention employing suitable pneumatically governeddevices in combination with a piano action; but as will appear to thoseskilled in the art, the invention is susceptible of embodiment invarious constructions and organizations other than that particularlyshown and described herein. It will appear likewise that it is notindispensable that all the features of the invention must be usedconjointly, since their respective substantial advantages may accruefrom their separate application in any practicable manner to a suitableinstrument.

The single figure of the accompanying drawings in a diagrammaticrepresentation of a typical piano action with Operating and governingmeans exemplifying the application and utility of the invention.

- Referring to the drawings a. striker or player pneumatic 1 isprovidedhaving a sticker 2 to act upon a wippen 3 and thereby operatethe usual piano action, as well leads to a wind chest for the motorpneumatics each of which has a secondary valve 8 controlled by a primaryvalve 9 operated from a tracker board T through a duct 10 in the usualmanner.

The wind trunk 7 communicates with a regulated wind chest 12. A highexhaust chest 14 arranged for communication with the chest 12 may beconnected by a trunk 15 with any source of pneumatic exhaust, such as adiagrammatically shown feeder bellows 16, which may be of anypracticable type.

In the illustrative apparatus of the drawings, the striker pneumatics 1may be operated by the exhaust in the regulated exhaust chest 12. Inorder to vary the operation of the striker pneumatics, this regulat-edexhaust may be varied by subjecting it more or less to the influence ofhigh exhaust in chest 14. For this specific purpose a port 30 controlledby a valve 31 is provided between the high exhaust chest 14 and theregulated exhaust chest 12.

The valve 31 may be operated by any suitable means, preferably byapparatus of the general character of that herein illustrated. In thisspecific apparatus the stem 32 of the valve 31 is connected to a movableboard 33 of a bellows apparatus presently described; said board beinghinged at 17. Such apparatus has a three-fold function for controllingthe valve 31, it automatically produces incremental changes in playingintensities; it performs a regulating function, that is, it maintainsany given playing intensity whether one or many notes be sounded; and itautomatically produces continuously progressive changes in playingintensities for crescendo and diminuendo purposes.

It is preferable with such apparatus that the means for varying thegeneral range of expression changes are combined, although it will beobvious that other apparatus, having any one or all of the capacities ofthe apparatus herein described, may be combined therewith to advantage.Following a brief description, in the sequence indicated, of the threecapacities of the apparatus acting through the bellows board 33, theembodiment of the further means referred to will be described. As thedescription proceeds it will be obvious that the invention is notdependent upon the specific details of construction secured to themovable board 33 and its the pressure in the bellows 37, bei

less than atmospheric pressure, sai bellows in effect exertscontinuously a uniform up- '20 control the valve 31. a

upper board to a stationary plate 38. A condition'of partial exhaust ismaintained at all times in the bellows 37 as presently described. Thedegree of exhaust in bellows 37 may be varied, but for the present thisfunction may be disregarded and the pressure within the bellows actingupon the board 33 .may be considered uniform. Thus, always ward ull onthe boardv 33 contributing to Ducts 40, 41 and 42 enter respectively thebellows 34, 35 and 36. Each duct may be controlled by any practicablevalve mechanism to admit to its -bellows either atmospheric pressure, orregulated pressure from the chest 12; and regulated pressure may beadmitted to the bellows selectively, while'atmospheric pressure will bepresent in those bellows, if any, which do not contain regulatedpressure. Whenever regulated pressure is present in any one or more ofthe bellows 34, 35 and 36 the effect thereof is to produce a downwardpull upon the board upward pull which results from the-condition ofpartial exhaust in the bellows 37, the two contributing to control thevalve 31. High exhaust in the chest 14 exerts some downward pressureupon the area of the valve 31 itself; and regulated pressure in thechest 12 exerts some upward pressure upon the area of the valve. Sinceregulated pressure is usually greater, it generall' predominates and theresultant upon the val i e itself is an upward pressure which combineswith the resultant of the pressure in the several bellows to completethe control of the valve 31.

The construction and arrangement of the apparatus may be such that theopposed up; ward and downward acting forces control the valve and tendto hold it in a balanced condition. For example, if regulated pressurebe present in all three of the bellows 34,35 and 36, the downward pullof these bellows upon the board 33 is at its maximum and tends to closethe valve 31 and minimize theopening between the chests 12 and 14. Underthese circumstances, playing intensities, as controlled by this portlonof apparatus, will be at the minimum. The bellows 34, 35 and 36 willthen operate substantially as a single regulator pneumatic formaintaining a uniform degree of exhaust in the 33. This downward pull isopposed by the.

regulated pressure chest whether one or many notes are concurrentlysounded. A

*board 33 through bellows 34 and 35 will be permitted to increase.Therefore the apparatus will 0 erate to regulate playing intensities ata higher level.

Regulated pressure or atmosphere may be admitted to the several bellows34, 35 and 36 selectively or in combination. To those skilled in theart, it will be readily understood that several well defined grades ofplzfiygingintensity may thereby be estab- Upon admitting atmosphere toall the bel lows 34, 35 and 36-. the forces acting upward upon the valve31 will so far predominate as to open'the valve to enlarge communicationbetween the chests 12 and 14 to the maximum.

Any suitable means may be adopted to govern .that part of the regulatingmechanism which operates through bellows 34, 35 and 36 to initiatedifferent substantiall dis tinct grades of regulated tension. erein theduct 40 connects the bellows 34 with a valve chamber 50 having a port toatmosphere and a port to a chamber 60 which is connected tothe-regulated pressure chest 12 through a passage 61. A duplex valve 51is mounted in valve chamber 50'and is controlled by a diaphragm 52 of adiaphragm chamber 53. A duct 54 leads from said diaphragm chamber to avent in the tracker T, correspondingly numbered. Thev parts 50-55described in connection with duct 40 are triplicated for ducts 41 and42, the cor-, responding parts of the valve mechanism for the latterbeing indicated by the numerals 50, 51, etc., with indices a forthevalve mechanism for duct 41,'and b for the valve mechanism for valve 42.

The manner in which the valves 51, 51 and 51? may be controlled from thetracker will be sufficiently obvious to those skilled in the art so thata detailed description is unnecessary. Sufiiceit to say that when anyone of the tracker vents is open to atmosphere the bellows correspondingthereto will also be opened toatmosphere, and when a tracker vent isclosed to atmosphere its corresponding bellows will be opened toregulated exhaust.

The preceding description has been devoted to an illustrative form ofapparatus by which substantially distinct grades or degrees of regulatedexhaust may be established .for playing notes at substantially distinctlizes a pneumatic system, about to be described, which exerts apneumatic pull through the bellows 37 in opposition to the bellows 34,35 and 36; said pneumatic pull being maintained substantially uniformand the valve chamber 107 and the pneumatic 101 and a by-pass around thescrew 119 is provided by passages 121 and 122. When it is desired tocompensate for an extreme fluctuation in the pneumatic condition ofpneumatic 101, the by-pass 121-122 may be opened. By-pass duct 121122may be closed by a valve 123 mounted upon a diaphragm of a diaphragmchamber 124. This chamber is connected by a duct 125 wlth a valvechamber 126 having a port 127 to atmosphere and a port 128 to exhaustchamber 111. A valve 129 controls ports corrected when necessary. Forconvenience 27 nd 128. Normally valve 129 is seated in that part of thedescription immediately following, the capacity of the apparatus toproduce incremental changes in playingintensities may be disregarded andit may be assumed that regulated exhaust is present in board 33 in thevalve 31.

all the bellows 34, 35 and 36 with the result of a maximum downwardpressure on the The bellows 37 is connected by a duct 100 with apneumatic 101, a spring 102 is fastened to the movable board ofpneumatic 101 and to an adiustable screw 103 threaded in a block 104. Astop 105 is provided to limit the expanding movement of the pneumatic101.

The pneumatic 101 may be exhausted through a duct 106 opening to a valvechamber 107 having a port 109 to atmosphere and a port 110 to an exhaustchamber 111, preferably connected to high exhaust. A valve 112 ismounted in chamber 107 and is con trolled by a diaphragm 113 of adiaphragm chamber 114. Diaphragm chamber 114 may be exhausted through ableed 115 and atmosphere may be admitted thereto through a duct 116 andport 117. The opening of the port 117 is controlled by a valve 118 andas will-be readily understood the eflective opening of this portrelatively to the size of the exhaust bleed 115 will control theoperation of the diaphragm 113 and the valve 112, which in turn controlsthe degree of exhaust in neumatic 101 and bellows 37.

ommunication between pneumatic 101 and valve chamber 107 through duct106 is somewhat restricted by an adjustable screw 119 which slightlyretards the action of the valve 112 upon the pneumatic 101. Upon aslight fluctuation in the degree of exhaust in pneumatic 101 the valve112 is automatically operated, as hereinafter described, to restorethereby in efi'ect maintaining the degree of exhaust the samesubstantially uniform. This restoration will be slightly retarded andrendered more delicate and refined because of the interposition of theobstruction 119.

For the purpose of more rapidly restoring the intended normal pneumaticcondition of pneumatic 101, a second adjustable obstruction screw 120 islikewise interposed between to close exhaust port 128 and openatmosphere port 127 thereby admitting atmosphere to duct 125 anddiaphragm chamber 124-. This ermits valve 123 to be normally seated to cose by-pass 121. Upon an extreme fluctuation of the pneumatic conditionin the pneumatic 101, the valve 129 is automatically lifted to exhaustdiaphragm chamber 124 and open by-pass 121122, thus perilrbitting a morerapid fiow of air along duct The valve 129 is governed by diaphragm 130of a diaphragm chamber 131 which communicates by aduct 132 with a port133 ad jacent the port 117, the port 133 being controlled by the valve118. The usual exhaust bleed for diaphragm chamber 131 is provided by ableed passage 134.

The valve 118 is operated by an arm 137 pro ecting from the movableboard of the pneumatic 101 and is so arranged that the port 117 will befirst opened to operate valve 112 and thereby correct a variation in thepneumatic condition of pneumatic101. Only thereafter if the expansion ofthe pneumatic 101 is sufficiently great, will port 133 be opened tocause a more rapid correction of the intended normal pneumaticcondition.

The pneumatic 101 is controlled by the differential between the pull ofthe spring 102 and the action of the exhaust within the pneumatic. Withthe described arrangement of valves, these opposed forces tend to holdthe pneumatic 101 in balance. For example, the pneumatic tends tocollapse to that point at which the atmosphere bleed 117 is maintainedat such a capacity that the degree of exhaust in the diaphragm chamber114 holds the valve 112 in that position in which the relative exhaustand admission of atmosphere past the valve 112 determines a degree ofexhaust within the pneumatic 101 which just balances the pull of thespring 102. Any influence tending to disturb this condition of balancewill be promptly compensated so that the ultimate effect is to maintainwithin the regulator tension system a subsantially uniform degree ofexhaust which, as will appear to those skilled in the art. will bedetermined ultimately by whatever tension may be given matic 101 besomewhat greater than that of bellows 37 so that the expanding andcollapsing movements of the pneumatic 101 (in response to similarmovements of the bellows 37) are much less in extent. With such anarrangement the minimized movements of the pneumatic 101 produce onlyslight elongations and contractions of the spring 102, and thereforeproduce only minimum changes in the tension of the spring.

That part of the apparatus just described, in addition to its capacityfor maintaining substantial uniformity of tension upon the regulatorpneumatic, (herein exemplified by, bellows 34, 35 and 36) also possesesthe capacity of varying playing intensities by varying the upward pullon the regulator and of controlling this'variation at differcut speeds.

If the pneumatic 101 is collapsed beyond its position of normalself-adjustment the spring 102 will be elongated, thereby increasing itstension and caus1ng an accompanying increase in tension of the a1rcondition in pneumatic 101 and bellows '37. This will result if thevalve 112 is raised and held in raised position for a substantial lengthof time, that is,'until the pneumatic 101 is completely collapsed. Airwill be withdrawn from pneumatic 101 through the small opening formed bythe obstruction screw 119 and the increase in tension will thereforetake place at a relatively slow speed. 7

This operation of the pneumatic 101 ultimately causes a slow increase onthe upward pull of the movable board 33 and such a variation of one ofthe forces controlling the valve 31 causes a 'slow continuouslyprogressive increase in playing intensities.

If the valve 112 is lowered to close port 110 and open port 109,atmosphere will be admitted to pneumatic 101 past obstruction screw 119and permit a slow restoration of the pneumatic 101 to its normalposition;

This operation, slowly decreases the upward pull on the board 33 withthe ultimate result of a slow continuously progressive decrease inplaying intensities.

If the valve 129 is raised simultaneously with valve 112 the pneumatic101 will be collapsed at a greater speed, due tothe opening of theby-pass 121-422. If thereafter valve 112 is lowered and valve 129 heldin raised position pneumatic 101 will quickly expand. These twooperations result respectively in a fast, continuously progressiveincrease or decrease in playing intensities.

Such changes in playing intensities as are described in the precedingparagraphs are commonly termed crescendo and diminuendo effects".

The above described operations of the valve 112 and 129 for producingcrescendos and dimenuendos ma be controlled by any practicable means. 1*or illustration the diaphragm chamber 114 may be connected to thetracker by a duct 138 opening to a tracker vent correspondingl which maybe opened or close tions in a music sheet. The aphragm chamber 131 ma besimilarly connected to the tracker bar y a duct 139. As will be readilyunderstood by those skilled in the art the regulating mechanismmay thusautomatically roduce crescendos and diminuendos at ifferent speeds underthe control of the note sheet.

The manner of properly coordinating the operations of the several partsof the regulating mechanism under the control of a perforated musicsheet will be sufiiciently obvious to those skilled in the art and neednotbe described in detail herein.

The arts of the apparatus acting through the be ows board 33 and havingthe threefold capacity for automatically producing incremental changesin laying intensities, for regulating playing mtensities, and forautomatically producing continuously progressive changes in pla mgintensities, having been sufficiently by which the extent of intensityvariations may be increased or the average level of playing intensitiesmay be raised, will now be described.

In view of the fact that the conditions surrounding the use'of anautomatic player piano vary greatly with every instrument, it isdifficult in their manufacture to give the parts such primary adjustmentaswill produce the most satisfactory effects. This fact, in connectionwith the varying tastes of numbered b perforaescribed, themeansdifferent piano users, makes it extremely desirable to haveassociated with the apparatus for automaticall obtaining expressionvariations, additiona means to control or vary from time to time theextent of expression changes; specifically to increase the average levelof playing intensity. It is often desirable to raise the average levelof playing intensities to impart a slightly higher intensity to thenotes which would normally be finement of operation inherent in themechanism or the effects produced by the relative character of thechanges from one intensity to another.

The operation of the instrument in certain respects might of course becontrolled by varying the expression mechanism actuating perforations inthe note sheet; but obviously it is impracticable to do so because sucha course would necessitate specially designed note sheets for eachindividual instrument. It is desirable to have the means for varying therange of expression changes, capable of operation to produce differenteffects in the ultimate playing of the instrument at different times andunder different circumstances from the same combination of note sheetperforations. In order that the continuity of expression variations andthe relative character of the expression'changes may not be. materiallydisturbed it is desirable that the means now referred to operate toeffect substantially all expression changes proportionately, therebypreserving continuity in the automatic expression governing mechanism.That part of the present invention presently to be described places theoperation of the instrument under the control of the user substantiallyin the manner suggested above. That part of the apparatus about to bedescribed may also operate to vary the several increments of intensitychange pre determined by that part of the expression governing mechanismacting through bellows 34, 35 and 36. It may also operate to modifycrescendoeffects by increasing the loudness of playing at substantiallyevery point in the crescendo thereby shortening the period of thecrescendof Diminuendo effects may be similarly modified.

In the specific embodiment of the invention disclosed in the drawings,means are provided to cooperate with the previously described bellowsapparatus controlling valve 31 and to supplement the forces tending toopen port 30 thereby increasing playing intensities. The regulator valvestem 32 is herein extended downwardly through the regulated exhaustchest and carries an adjustable button 250. A bellows 251 is suitablymounted upon some stationary part of the instrument and fast to itsmovable board 252 is an arm 253 adapted to bear against the button 250as the bellows 251 is collapsed. A light spring 254, whose functionswill be later referred to in more detail, tends to hold the bellows inexpanded position.

The pneumatic 251 is connected through a valve 255 with a source ofexhaust, preferably regulated exhaust in wind chest 12. A duct 256 leadsfrom the interior of the bellows to the valve and a duct 257 leads fromthe wind chest 12 to the valve. Means may be provided for varyingoperative connection between these two ducts and the same will be laterreferred to, but for the present it may be assumed that the ducts 256and 257 are directly connected whenever the bellows 251 is brought intooperation.

The bellows 251, when subjected to exhaust pressure, will exert anupward thrust through the arm 253 upon the valve stem 32; the power ofthe thrust depending upon the area of the bellows, the leverage of thearm and tension of the spring 254. The spring 254 is preferably soadjusted that it will have a slight though constant effect throughoutthe operation of the bellows 251 and will have a predominating effect incontrolling the operation of-the bellows 251 when playing intensitiesare at or approachlng the lowest point.

It will be'apparent to those skilled in the art that the bellows 251will, when subjected to exhaust pressure, contribute a factor in thebalancing equation controlling the operation of the regulator valve 31.

It is convenient at this point to summarize the factors heretoforementioned which nor mallyappear in this balancing equation, whichdetermines the operation of the regulator valve, thereby governingplaying intensities. The upward acting forces tending to open theregulator valve and increase playing intensities are (1) thedifferential between atmospheric pressure on the underside of bellowsboard 33 and exhaust pressure within bellows 37, (2) the differentialbetween high exhaust in chest 14 and regulated exhaust in chest 12acting upon the regulator valve 31. The downward acting force tending toclose the regulator valve and thereby decrease playing intensities is(1) .the differential between atmospheric pressure on the upper side ofbellows board 33 and regulated exhaust pressure within any one or all ofthe bellows 34, 35 and 36. 110

The bellows 251 when in operation adds to the above upwardly actingforces tending to open valve 31 by the differential be tween atmosphericpressure on the outer surface of the movable board 252 and regulated bereadily understood by those skilled in the art and will simplify thefollowing discussion. It will also be convenient to regard the operationof the step change mechanism as dependent solely upon a change in areaof the regulatOl lather than a change in area combined with a change inleverage on the bellows board 33.

Omitting the bellows 251, or in other words assuming that the ducts 256and 257 are not connected the normal balancing equation will be asfollows: The u wardpull of exhaust within the pouch 3 plus the area ofthe regulator valve 31 times the difference between. high exhaust andregulated exhaust, will equal the regulated exhaust times the actingarea of the regulator. Con necting the bellows 251 with the chest 12will establish a new balancing equation as follows: The upward pull ofexhaust within pouch 37, plus the area of the valve 31 times thedifference between high exhaust and the newly established regulatedexhaust, plus the effective area of'bellows 251 times the newlyestablished regulated exhaust, minus the effective power of the spring254, will equal and balance the newly established regulated exhausttimes the acting area of the regulator. In the specific apparatusdisclosed the foregoing equation will explain the operation thereofwithin limits established byrthe capacity of the instrument. Obviously,a re-arrangement of parts may result in a change in the foregoingequations and it will be understood that they are herein given merely toillustrate a single specific embodiment of the invention.

For convenience of' description and ex-' Y tensity while numeral 20 willindicate the loudest playing intensity. Therefore the incremental,crescendo and diminuendo changes will be effected within the compass ofthis scale from 4 to 20. If the apparatus is adjusted for seven definedgrades of playing intensity, as might be the case with the presentapparatus,t ese incremental changes may be assumed to establish playingintensities respectively at 4, 4.5, 5.5, 7.5, 11, 18 and 20 in theimaginary scale. It may further be assumed that-a crescendo may beinaugurated when the playing intensity is fixed at any one of the sevenpoints in the scale, except the last, and will inoperation, if continuedlong enough, raise playing intensities, at a greater or less speed asmay be determined by the apparatus, from the point at which it isinaugurated to the highest intensity.

. Thereafter a diminuendo operation may be inaugurated and decreaseplaying intensities to any point determined by the step changemechanism.

It may-also be assumed that playing intensities vary directly with avariation in the degree of regulated exhaust so that as playingintensities vary from .4 to 20 regulated exhaust will also vary from 4to 20 and further that if regulated exhaust is at 11, playingintensities will also be at 11.

Assuming that the expression mechanism heretofore described is set tofix playing intensities at 11 in the supposed scale, and disregardingfor the moment the capacity of the apparatus for varying playingintensities from that point, let it be understood that it is desired toincrease playing intensity 11 to a point approximating the full power ofthe instrument and that for this purpose the bellows 251 is connectedwith the regulated exhaust chest 12. [By thus throwing into operationthe bellows 251 the forces tending to 0 en valve 31 and'increase playingintensitles will be increased by the pull of regulated exhaust uponbellows board 252. This pull of regulated exhaust will be opposed by thespring 254 but the spring is preferably so ad usted that at this pointit will be overbalanced and the pneumatic will tend to collapse. Thistendency to collapse may raise the valve 31 slightly if conditionsrequire a uniform draft upon regulated exhaust. Thus raising the valve31 subjects regulated exhaust to the influence of high exhaust to agreater extent and increases the degree of regulated exhaust. Thisincrease in regulated exhaust being communicated to the bellows 251further increases the upward thrust upon the valve 31. Simultaneouslywith the increase of the upward thrust of bellows 251 there will occuran increase in the downward pull of regulated exhaust upon bellows board33 due to the increase in the degree of regulated exhaust actingthereon. If under these circumstances the effective area of the movableboard of the regulator is greater than the effective area of bellowsboard 252 a balance will soon be reached wherein the paratus whenbellows 251 is inactive by the V expression mechanism actuatingperforations of the note sheet may be raised to'20 by the operation ofthe bellows 251.

The degree of regulated exhaust and playing intensities having beenraised in the above manner they will be maintained uniform at this pointin spite of uneven drafts upon regulated exhaust due to the pla ing ofvarying numbers of notes concurrent y in substantially the same manneras heretofore the operation of the bellows 251.

described in connection with the maintenance of uniformity of playing bythe main expression governing mechanism. If for any reason there is aninflux of atmosphere to chest 12 tending to reduce the degree ofregulated exhaust, the downward-pull upon the bellows board 33 will berelaxed \tending to permit the valve 31 to open. But simultaneously theupward thrust of bellows 251 will also be relaxed. However, theconnection between the arm 253 and the valve stem 32 being such that thebellows 251 in expanding merely causes its arm to fall away from thebutton .250 theuniformity of playing will be substantially maintained bythe main expression governing mechanism.

Upon the restoration of the predetermined degree of exhaust in chest 12the forces in the balancing equation will resume their former values tomaintain playing intensities at the predetermined level.

It is preferable that the lowest playing intensity determinable by themain expression governing mechanism be unaffected by Assume that theexpression mechanism actuating perforations are set to determine playingintensities at 4, the minimum in the supposed scale, under thesecircumstances the operation of the bellows 251 would tend to increasethe upward acting forces operating upon the regulator 'valve by anamount equal to the pressure of regulated exhaust times the effectivearea of the bellows board 252. If therefore, the spring 254 is soadjusted that it will now balance the force tending to collapse bellows251 there Wlll be no upward thrust and the balancing equationcontrolling valve 31 will not be disturbed. This is the preferablearrangement and the parts may be primarily adjusted to this end.

\Upon the increase of regulated exhaust determined by the note sheetwhich would normally raise playing intensities to 4.5 m the supposedscale the increased upward thrust of bellows 251 will overcome the powerof the spring and the resultant will be an upward thrust upon the valve31 which will enter into and constitute a factor in the balancingequation controlling the regulator valve. At this intensity the actingarea of the movable board of the regulator is relatively lar e and theslight increase in regulated exhaust acting upon the effective area ofbellows board 252 will soon be balanced by the increase in regulatedexhaust acting upon the larger area of the movable board of theregulator. Thus the playing intensities will be increased only slightly.As the playing intenslties are normally raised step by step in thesupposed scale the bellows 251 will have an increasing influence in thebalancing equation until, as

present apparatus.

previously described, at intensity 11 it will increase playingintensities to intensity 20, which approximates the full power of theinstrument.

=With the proper primary adjustments and relative porportionment ofareas exposed to regulated exhaust the normal scale may be varied asfollows: Intensity number 1 may remain at 4. Intensity number 2 may beincreased from 4.5 to 4.6; number 3 from 5.5 to 6.1; number 4 from 7.5to 9.6; number 5 from 11 to 20; number 6 from 18 to the full power ofthe instrument which is supposed to be 20, and obviously number 7, beingthe full power of the instrument cannot be further increased. Heretoforethe step changes in playing intensities obtained by what in effect is avariation in the area of the movable board of the regulator have beenconsidered in their relation to the operation of the bellows 251. Duringthat consideration it has been assumed that the upward pull upon theregulator valve due to the presence of exhaust within bellows 37 hasremained uniform, and such will be the case with the The bellows 251will have an effect upon crescendo expression changes which in generalcharacter will be similar to the effect produced at a correspondingpoint in the scale of intensities determinable by the step changemechanism. There may however, be a difference in extent, due to the factthat in a crescendo operation the area of the movable board of theregulator exposed to regulated exhaust is not necessarily varied. Forcomparison consider the effect upon regulated exhaust at the point 11 ina crescendo and the corresponding effect at the point 11 determined bythe step change mechanism. As previously noted in order to produceintensity 11 through the agency of the step change mechanism theeffective area of the movable board of the regulator bellows isdecreased. Thus decreasing the area causes the balance between theupward thrust of bellows 251 and the downward pull of the regulatorbellows to be attained when regulated exhaust has been increasedsubstantially to 20.

If it is assumed that a crescendo operation has been begun at the lowestintensity (point 4) the entire area of the regulator bellows will thenbe exposed to regulated exhaust. Therefore the difference between theregulator bellows area. and the area of bellows 251 is greater and thebalance will be reached somewhat sooner or, with the same assumed valuesat substantially 13. From this point on the bellows 251 will have anincreasing effect in the balancing equation and will cause the highpoint of the crescendo to be reached sooner than it otherwise wouldwithout bellows 251 in *operation. .Therefore the bellows 251 will havean increasing effect upon the crescendo as it raises playing intensitiesgradually from 4 to 20.

For further illustration it may be assumed that a crescendo operationhas been inaugurated from the 4th intensity step i. e. point 7 5mthesupposed scale. Under such circumstances the acting area of the reulator bellows may be considerably less t an in the foregoing assumedcase. Therefore the difference between the regulator bellows area andthe area of bellows 251 is less than before and the new balance will notbe reached as quickly. This will require a greater increase in regulatedexhaust, before the balance is reached and with the same assumed valuespoint 11 in the normal crescendo will now become 15.5.

Throughout crescendo operations the lowest possible point of a,crescendo that is point 4 in the supposed scale, may not be changed bythe introduction of regulated exhaust to. bellows 251.

The opposite effect of the bellows 251 during a diminuendo operationwillbe obvious to those skilled in the art.

I It will be seen from the foregoing description that the part of theinvention operating through pneumatic 251 embodies convenient means forvarying the range of effects which can be produced. by the automaticaction of the instrument. Such a device is of extreme value in that itpermits the instrument to be readily adapted to the surroundingcircumstances amid which it is used. Furthermore it permits, what may betermed the contrast in expression to be increased for certain selectedcompositions or parts of the same composition.

As far as the step change mechanism is concerned it modifies theultimate effect of expression actuating perforations so that theapparatus produces larger increments of change in intensity from onestep to the next without however destroying the delicacy of playing inthe lower ranges of intensity. n effect it renders the scale ofintensities elastic in that the u per range of intensity change israised wh1le the lower or normal minimum intensity may not be effected.For illustration, assume a composition wherein the expression is variedbetween the first four intensities, that is, from 4 to 7.5. With thesame note sheet the range of expression changes can be extended throughthe agency of the pneumatic 251 so that the expression may vary between4 and 9.6, thus producing greater contrast in the composition. Orescendoand diminuendo changes may be similarly effected without a variation inthe mote sheet-perforations or in adjustment of the main apparatus. Acrescendo operation through the pneumatic 251, will be caused to reach ahigher point in a given time than would be the case in the absence ofthe pneumatic 251.

It has been assumed that the pneumatic 251 may be connectedalternatively with a source of exhaust, for instance, the regulated windchest 12, or with atmosphere; thus rendering the intensifier operativeto its full extent or entirely inoperative. Means may however beprovided whereby the pneumatic 251 may have a different effect to raiseplaying intensities by a less amount and such means are herein providedthrough the a ency of the valve 255.

Va've 255 previously referred to, comprises a valve casing 258 havin amovable piston 259 which is adapted tos ide endwise and may be operatedby any convenient means such as a lever 260 mounted preferably upon thekey rail of the piano. The movement of the valve piston 259 is limitedby a pin 275, which moves in a slot 276 in the valve casing. The ducts256 and 257 open to the interior of the valve through ports 261 and 262respectively while a port 263 provides for the admission of atmosphereto the interior of the valve. The valve piston is chambered to form a Dvalve and the valve is preferably so proportioned that the port 261 isalways open to the valve chamber while the ports 262 and 263 may beplaced in communication with the valve chamber by operating the lever260. When the port 262 is wide open the port 263 will be closed. This isthe position shown in the drawings and such a position of the valveplaces duct 257 in full communication with duct 256, with the resultthat playing intensities are increased by the maximum increaseattainable through the operation of the bellows 251.

If the valve piston is moved to the left it will gradually close port262 and open port 263 allowing atmosphere to bleed into the valve andthereby reduce the degree of exhaust in the pneumatic 251 relatively tothe degree of exhaust within wind chest 12.

This will decrease the upwardly acting force lis a new balancingequation which will so control the apparatus as to increase playingintensities by a less amount than the predetermined maximum increase. Asthe movement of the valve piston continues toward the left the port 262will be finally closed and the port 263 will be open, thus the valveeffectually cuts off all communication between wind chest 12 and bellows251 and opens the latter to atmosphere. Admitting atmosphere to bellows251 renders it entirely inoperative and the playing intensities will begoverned solely by the main regulating apparatus acting through bellowsboard 33. The results obtained by thus decreasing the degree of' exhaustin bellows 251 relatively to thatin the regulated exhaust chest will beapparent to those skilled in the art from the foregoing description andfurther explanation is deemed unnecessary.

It should be understood that in the receding description the scale of'intenslties from 4 to 20 and the stated increases at any given point inthis scale are assumed and arbitrary points selected merely forpurposesof illustration, although the lower and upper limits of the scale happento correspond to the height to which a column of water would be drawn bythe regulated exhaust at the lowest and highest playing intensitiesrespectively.

It is to be understood that the principal features of the presentinvention are not necessarily limited to' use in combination with theparticular expression governing means herein disclosed but that the samemay be variously combined with other means for normally regulatingintensities and with means forrproducing crescendo and diminuendochanges. Furthermore the present invention is not limited to thespecific details, construction, organization, and mode of operationhereinbefore described for the purpose of illustration; on the contrary,the invention may be variously modified and embodied within the scope ofthe subjoined claims.

I claim as my invention:

1. An automatic musical instrument comprising, in combination, playingactions; a main source of power for operating said playing actions; athrottle valve between the main source of power and the playing actions;expression governing means operatively connected to said throttle valveto vary the degree of power transmitted from the source to the playingactions; and supplementary expression governing means responsive tovariations in and tending to increase the degree of power transmitted tothe playing actions as governed by said first named expression governingmeans.

2. An automatic musical instrument comprising, in combination, playingactions; a main source of power for operating said playing actions; athrottle valve between the main source of power and the playing actions;expression governing means operatively connected to said throttle valveto vary the degree of power transmitted from the source to the playingactions; and supplementary variably acting pneumatic means tending toincrease the degree of power transmitted to the playing actions asgoverned by said first named expression governm means.

' 3. n automatic musical instrument comprising, in combination; playingactions; a main source of power for operating said playing actions; athrottle valve between the main source of power and the playing actions;a regulating pneumatic operatively connected to said throttle valve,having con.- nection with regulated air governed by said throttle valveand tending to close the same;

and a supplementary regulating pneumatic also having connection withregulated air operatively connected to and tendlng to open said valve.

4. An automatic musical instrument comprising, in combination, playingactions; a main source of power for operating said playing actions; a.throttle valve between the main source of power and the playing actions;expression governing means including a regulating pneumatic operativelyconnected to said throttle valve and tending to close the same; andsupplementary. expression governing means having connection withregulated air governed by said throttle valve and tending to open saidvalve.

5. An automatic musical instrument comprising, in combination, playingactions; a main source of power for operating said playing actions; athrottle valve between the main source of power and the playing actions;a tracker; tracker controlled expression governing means operativelyconnected to said throttle valve to vary the degree of power transmittedfrom the source to the laying actions; and supplementary expressiongoverning means responsive to fluctuations in and tending to increasethe degree of power transmitted to the playing actions by said trackercontrolled expression overning means.

6. n automatic musical instrument comprising, in combination, playingactions; a main source of power for operating said playing actions; athrottle valve between the main source of power and the playing actions;a tracker; tracker controlled expression governing means operativelyconnected to said throttle valve to vary the degree of power transmittedfrom the source to the playing actions; and supplementary pneumaticmeans responsive to fluctuations in and tending to increase the degreeof power transmitted to the playing actions as governed by said trackercontrolled expression 'OVGIIllIlg means.

7. n automatic musical instrument comprising, in combination, playingactions; a main source of power for operating said playing actions; athrottle Valve between the main source of power and the playing actions;a tracker; tracker controlled expression governing means including aregulating pneumatic operatively connected to said throttle valve,having connection with regulated air governed by said throttle valve andtending to close the same; and a supplementary regulating pneumatichaving connection with regulated air operatively connected toand tendingto opensaid valve.

8'. An automatic musical instrument comactions; a tracker; trackercontrol ed exression governing means including a regu-- ating pneumaticoperatively connected to saidthrottle valve, having connection withregulated air governed by said throttle mouse change in playingintensities; and means for progressively varying the increments ofchange inaugurated by said last named means. i

13.-'An automatic musical comprising, in combination, playing actions; amain source of power for operating said playingsact'ions; a throttlevalve be tween the main source of power. and the playing actions;expression "governing means for inaugurating and maintainingsubstantially distinct increments of change in playing. intensities; andmeans for pro v l d. t ndi t l e th a a p gressively increasing theincrements of plementary regulating pneumatic operathange so inauguratedby said last named tively' connected to said valve; and means to connectsaid pneumatic alternatively. to

' main source of power for operating said playing actions; a throttlevalve between regulated airor to atmosphere. 9. An automatic musicalinstrument comprising, in combination, playing actions; a

the main source of power and playing actions; expression governing meansoperatively connected to said valve for 1naugu-' rating and maintainingsubstantially distinct increments of change in'playingintensities; andsupplementary expression governing means to increase the respectiveincrements of change'inaugurated by said last named means. I v v 10. Anautomatic musical instrument comprising, in combination, playingactions;a main source of power for operatlng said playing actions; a, throttlevalve be- :tween the main source of power and the plalying actions; atracker; tracker contro led expression. governlng means for inauguratingand maintaining substantially distinct increments of change in playingintensities; and supplementary expression governing means to increasethe respective ncrements of change inaugurated by sald trackercontrolled means.

11. An automatic musical instrument comprising, in combination, playingactions; at main'source of power for operatingsaid playing actions; athrottle valve be-- tween the main source of power and the pla ingactlons; a tracker; tracker contro led expression governing means forinaugurating and maintaining substantially distinct increments of changein playing intensities; and manually contr lled means to increase therespective increments of change inaugurated by said tracker controlledmeans.

12. An automatic musical instrument comprising, in combination, playingactions; a main source of power foroperating said playing actions; athrottle valve between the main source of power and the playing actions;pneumatic expression governlng means for inaugurating and maintainingsubstantially distinct increments of means. I

An automatlc musical instrument comprlsmg, 1n combination, playingactlons; a

instrument I main source of power for operating said maintainingsubstantially distinct increments or. change in playing intensities; andprogressivel increasing t e respective increments 0 change inauguratedby said tracker controlled means.

Al -automatic musical instrument comprismg, 1n combination, playingactions; a mam source of power for operating said playing actions; athrottle valve between the main source of power and the laying actions;a tracker; tracker contro led express'ion governing means forinauguratin and .malntamlng substantially distinct morements of changein playing intensities; and manually controlled means for progressivelymcreasmg the respective increments of change inaugurated by said trackercon- 10 trolled means. I

16. An automatic musical instrument comprising, in combination, playingactions; a main source of power for operating said playing actions; athrottle valve between 11 the main source of power and the playingactions; expression governing means for increasing playing intensitiesby distinct increments including a regulating pneumatic operativelyconnected tosaid throttle valve 118 and havmg' connection with regulatedair governed thereby; and a pneumatic acting upon said throttle valve inopposition to sald regulating pneumatic and connected to I regulated airfor enlargin the incremental 120 changes inaugurated by said expressiongovernmg means.

17. An automatic musical instrument comprising, in combination, playingactions; a

main source. of power for operating said playing actions; a throttlevalve between the main source of power and thelaying actions; a tracker;tracker control ed expression governing means for increasing playingintensities by distinct increments including a regulating pneumaticoperatively connected to said throttle valve and havingconnection withregulated air governed thereby; and a pneumatic acting upon saidthrottle valve in opposition to said regulating pneumatic and connectedto regulated air for enlarging the incremental changes inaugurated bysaid expression governing means.

18. An'automatic musical instrument com.- prising, incombination,'playing actions; a main source of power for operating saidplaying actions; a throttle valve between the main source of power andthe playing actions; a tracker; tracker controlled expression governingmeans fofincreasing playing intensities by distinct increments includinga regulating pneumatic operatively connected to said throttle valve andhaving connection with regulated air governed thereby; a

, pneumatic acting upon said throttle valve in opposition to saidregulating pneumatic and connected to regulated air for enlarging theincremental changes inaugurated by said expression governing means; anda manually controlled valve to govern said last'named means. i

19. An automatic musical instrument comprising, in combination, playingactions; a main source of power for operating said playing actions; athrottle valve between the main source of power and the playing actions;expression governing means including a regulating device of variableacting area operatively connected to and tending to close said throttlevalve; and a pneumatic operatively connected to and tending to open saidthrottle valve connected with a source of exhaust controlled by saidthrottle valve.

20. An automatic musical instrument comprising, in combination, playingactions; a main source of power for operating said playing actions; athrottle valve between the main source of power and the playing actions;expression governing means including a regulating device of variableacting area operatively connected to and tending to close saidthrottle'valve; a pneumatic operatively connected to and tending to opensaid throttle valve; and means to connect said pneuplaying actions; athrottle valve between the mam source of power and the playing ac-.tions; expression governing means including a regulating device ofvariable acting area operatively connected to and tending to close saidthrottle valve; a tracker; tracker controlled means to vary the actingarea of said regulating pneumatic; a pneumatic operatively connected tosaid throttle valve and said pneumatic alternatively with atmosphere orwith a source of exhaust controlled by said throttle valve.

An automatic musical instrument comprising, in combination, playingactions; a main source of power for operating said playing actions; athrottle valve between the main source of power and the playing actions;pneumatic expression governing means for inaugurating and maintainingsubstantially distinct increments of change 111 playing intensities; anda pneumatic operatively connected to said throttle valve and to a sourceof exhaust controlled thereby for progressively increasing theincrements of change inaugurated by said last named means.

An automatic musical instrument com prising, in combination, playingactions; a main source of power for operating said playing actions; athrottle valve between the main source of power and the playing actions;a tracker; tracker controlled expression governing means forinaugurating and maintaining substantially distinct increments of changein playing intensities; means for progressively increasing therespectrve increments of change inaugurated by said tracker controlledmeans, including a pneumatic operatively connected to said throttlevalve and to a source of exhaust controlled thereby for progressivelyincreasing the increments of change inaugurated by said last namedmeans.

24. An automatic musical instrument comprising, in combination, playingactions; a main source ,of power for operating said playing actions; athrottle valve between the main source of power and the playing actions;a tracker; tracker controlled expres- SlOIl governing means forinaugurating and maintaining substantially distinct increments of changein playing intensities; a pneumatic operatively connected to saidthrottle valve for progressively increasing the respective increments ofchange inaugurated by said tracker controlled means and havingconnection with regulated exhaust; and a manually controlled valve insaid connection.

25. An automatic musical instrument comprising, in combination, playingactions; a main source of power for operating said playing actions; athrottle valve between the main source of power and the playing actions;expression governing means operatively connected to said throttle valvefor varying expression b substantially continuous progression; andsupplementary means operatively connected to said valve for varying thespeed of the progression.

26. An automatic musical instrument com prising, in combination, playingactions; amain source of power for operating said playing actions; athrottle valve between the main source of power and the playing actions;expression governing means opera-' tively connected to said throttlevalve'for varying expression b substantially contin-' uons' progression;an supplementary pneumatic means operatively connected to said valve forvarying the speed of the progres- SlOIl.

27. An automatic musical instrument comprising, in combination, playingactions; a

main source of power for operating said playing actions; a throttlevalve between the tions; a tracker; tracker controlled means operativelyconnected to said valve to vary by. substantially continuous progressionthe degree of power transmitted from the source to the playing actions;a pneumatic operatively connected to said throttle valve and tending toopen the same to increase the effective speed of operation of saidtracker controlled means; and manually; controlled means foralternatively conneting said pneumatic to atmosphere or to a source ofexhaust controlled by said throttle valve.

29. An automatic musical instrument comprising, in combination,fplayingactions; a main source of power or operating said playing actions; athrottle valve between the maln' source of power and the playingactions; expression governing means operatively connected to and tendingto open said throttle valve for crescendo and diminuendo expressionchanges at predetermined speeds; and supplementary pneumatic meansconnected to said throttle valve and tending to open same to increasethe redetermined speed of the crescendo an diminuendo changes.

30. An automatic musical instrument comprising, in combination, playingactions; a

main source of power for operating said playing actions; a throttlevalve between the main source of power and the playing actions;expression governing means including a regulating pneumatic operativelyconnected to and tending to close said valve; supplementary expressiongoverning means including a pneumatic connected to and tending to opensaid valve and having connection with a' source of exhaust controlled bysaid valve; and means to diminish the operative effect of said lastnamed means.

31. An automatic musical instrument comprising; in combination, mainsource of power playing actions; a throttle valve between .the mainsource of power and the playing actions; exlpression governing meansincludinga regu atlng pneumatic operatlvely connected to and tending toclose said valve for varying playing intensities from a normal minimumto a predetermined maximum;

nected to and tending to close saidvalve for varying playing intensitiesfrom a normal minimum to a predetermined maximum; means including apneumatic acting upon said throttle valve and tendingto increase playingintensities so governed; and a sprin acting upon said pneumatic torender said last named means ineffective when playing intensities aregoverned at the normal minimum. 1

33. An automatic musical instrument comprising, in combination, layingactions; a main source of power playing actions; a throttle valvebetween the mam source of power and the playing actions; expressiongoverning means including a regulating pneumatic operatively connectedto and tending to close said valve for varying playing intensities froma normal minimum to a predetermined maximum; and means acting upon saidthrottle valve to vary playing intensities so governed and beinincreasingly eifective as playing intensities approach the maximum.

34. An automatic musical instrument com- I prising, in combination,playing actions; a

.to a predetermined maximum; and sup lementary means to vary theincrease in aying intensitles as inaugurated by sai -last or operatingsaid laying actions; a or operating said named means by a progressivelyincreasing proportion from the normal minimum to the predeterminedmaximum.

35. An automatic musical instrument comprising, in combination, playingactions; main source of power for operating said playing actions; athrottle valve between the main source of power and the playing actions;means to maintain uniformity of playing whether one or many notes aresimultaneously sounded; means to decrease the playing intensities from apredetermined maximum to a normal minimum; and supplementary means tovary the decrease in playing intensities as inaugurated by said lastnamed means by a progressively decreasing proportion from thepredetermined maximum to the normal minimum.

36. An automatic musical instrument comprising, in combination,1fplaying actions; a main source of power or operating said playingactions; a throttle valve between the mam source of power and playingactions;

progressively increasing with the increase in playing intensities.

In testimony whereof, I have signed my name to this specification this23rd day of November, 1917.

CHARLES R STODDARD.

Gertificate of (Correction It is hereby certified that in Letters PatentNo. 1,409,496, granted March 14, 1922,

upon the application of Charles F. Stoddard, of New York, N. Y., for animprovei ment in Automatic Musical Instruments, an error appears in theprinted specification requiring correction as follows:

Page 6, lines 117 and 118, strike out the comma and phrase that is, thecrescendo produced by the apparatus when bellows 251 is inactive andinsert the same to follow the word crescendofiline 19, page 8; and thatthe said Letters Patent should be read with this correction therein thatthe same may conform to the record of the case in the Patent Office.

Signed and sealed this 13th day of June, a. n, 1922.

KARL FENNING,

' Acting G'ommissioner of Patents.

